Automatic electric switch

ABSTRACT

An automatic electric switch has a base covered by a cap. The switch includes electromagnetic instantaneous and thermal excess current releases, stationary and movable contact portions, quenching devices and a switch lock mounted on a plate which extends at a distance toward the bottom of the base, whereby the instantaneous releases are located between the plate and the base. The instantaneous releases are holders for the movable contact portion and are inserted as a structural unit between the plate and the base.

' United States Patent Scheibel et al. 1 Apr. 25, 1972 [54] AUTOMATIC ELECTRIC SWITCH [56] References Cited [72] Inventors: Karl-Heinz Scheibel; Wilhelm l-iolzer, both UNITED TE PATENTS Amherst Germany 2,925,481 2/1960 Casey ..335/145 [73] Assignee: Siemens Aktiengesellschnit, Berlin & 2,934,620 4/1960 Middendm'fm Munich .cemany 3,016,435 1/1962 Schwartz ..335/38 3,324,429 6/1967 Ellenberger .....335/35 Flledi p 23,1970 3,517,355 6/1970 Cole ..335/16 [2!] Appl 74638 Primary Examiner-Harold Broome Related s Appncauon Data Attorney-Curt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick [63] Continuation-impart of Ser. No. 752,300, Aug. l3,

1968, abandoned. 57 ABSTRACT An automatic electric switch has a base covered by a cap. The [30] i Application Priority D switch includes electromagnetic instantaneous and thermal Aug. 23, 1967 Germany ..P 15 88 754.4 excess current releases, stationary and movable contact portions, quenching devices and a switch lock mounted on a plate [52] U.S.Cl ..335/35 which extend at a ist nce t w rd he o m of h base, [51] lnt.Cl. t ..H0lh 75/12 whereby the instantaneous releases are heated between the 5 plate and the base. The instantaneous releases are holders for Field of Search ..335/35, 23,16, 38,145,11

the movable contact portion and are inserted as a structural unit between the plate and the base.

6 Claims, 5 Drawing Figures PATENTEU APR 2 5 I972 1 SHEET 1 BF 2 AUTOMATIC ELECTRIC SWITCH The present application is a continuation-in-part application of pending patent application Ser. No. 752,300, filed Aug. 13, 1968, now abandoned for Electric Switch" and assigned to the assignee of the present application.

DESCRIPTION OF THE INVENTION The invention relates to an automatic switch having a socket covered by a cap. The switch includes electromagnetic, instantaneous, and thermal excess current releases or trips and also stationary and movable contact members and quenching devices. The switch further comprises a switch lock, mounted on a plate, which extends at a distance to the bottom of the socket, and the instantaneous releases are located between the plate and the base.

The construction of an automatic electric switch should be relatively simple, as a rule, in order to permit inexpensive production, and should be versatile in design, that is, a plurality of various parts should be utilizable in the same total construction of the switch. A known automatic electric switch comprises a basic switch portion provided with a switching mechanism drive, a switch lock, and the actual circuit member, which comprises the contact units and the mounted on switching chamber, in a manner whereby separate structural groups, such as the release or trip for the working current, the excess current and the short-circuit release or trip may be attached to said basic switch portion. The construction of the basic switch portion is relatively expensive and is, in many cases, insufficiently versatile.

Moreover, an electrical, multipole automatic switch is known wherein the short-circuit releases or trips, which, in this instance, are provided for all poles, with contact-separating members, may be designed as exchangeable structural units which can be calibrated for themselves. The units may be affixed to a preferred upper part of the insulating base plate of the switch, that is, by bolt or screw attachment with the terminal bars of the stationary contact members attached to the preferred part of the insulating base plate. Thus, the stationary contact portion and the movable contact portion are firmly connected to the basic part of the switch, whereby additional junction resistances occur at the bolt or screw connection in the circuit included in the switch.

Another known electrical automatic switch is disclosed in Austrian Pat. No. 172,562. The Austrian patent discloses that the electromagnetic instantaneous and thermal excess current releases or trips and the stationary and movable contacts and quenching devices, are inserted in a vat-shaped recess of the base. The recess is sealed by a lid or cover which houses the actual switch lock for the automatic switch. The switch lock itself is covered to the outside by a cap. When it becomes necessary to remove the instantaneous release or trip from the switching apparatus in this type of arrangement, such removal is possible only after the cap is removed and the switch lock is dismantled and the lid is removed.

These known automatic switches are improved by our invention in a simple manner whereby the instantaneous releases or trips are designed as supports for the movable contact portions and may be installed as a structural unit between the plate and the base. This permits a particularly advantageous current curve in the switch and a particularly simple design of said switch. The instantaneous release or trip and the movable contacts may be adjusted in a simple manner to the desired current conditions. It is especially preferred thereby to arrange between the contact part and the instantaneous release or trip, which remains stationary in the housing, a contact pressure spring which is also utilized as a closing spring.

A separate or special closing spring is thereby clamped in and the support of said spring is considerably simplified, since it does not have to bear against the housing. The spring does not have to bear against the housing, because after the insertion of the spring between the movable contact part and the instantaneous release or trip, the unit is installed into the base.

The instantaneous release thus abuts against the housing. A particularly expedient spatial utilization is provided in a switch for the current limiting separation of the contacts when the armature of the instantaneous release is designed as a tie bar. The width of the switch is not impaired by the arrangement of the tie bar if the armature penetrates the movable contact portion and is connected to an extension via which the movable contact part may be opened.

The switch lock comprises a rocker flap which is connected to the movable contacts by means of individual pull lugs. This makes it possible to impart a striking force to individual contact parts independently from the others. According to another feature of the invention, the rocker flap is loaded with a spring in a direction to separate the contacts. The rocker flap spring exerts a force greater than that of the spring disposed between the movable contact and the instantaneous trip thereby permitting the switch to be opened manually.

The rocker flap is loaded with a knuckle joint at a point away from its axis of rotation so that the switch may be operated manually by a turning toggle in a plane which is perpendicular to the opening direction of the contacts. In order to permit the switch lock to be unlatched by means of the armature of the instantaneous trip, a striker is provided on the side of the armature lying opposite the extension. This striker for unlatching the switch lock penetrates the plate and does not hinder the simple installation of the instantaneous trip.

According to still another feature of the invention, the instantaneous trip is adjusted by means of a leaf spring having two legs at .substantially with respect to each other. One leg of the leaf spring is in pressure contact with either the armature or the striker, the pressure being applied in a direction to close the contacts. The other leg of the leaf spring bears against two stationary supports between which the leaf spring can be stressed in flexure by an adjusting device so as to adjust the pressure applied by the other leg. It is advantageous to locate the leaf spring supports on the return iron of the instantaneous trip if the adjusting mechanism comprises a bolt or screw which threadably engages the return iron and whose head bears against the flat spring.

In order that the invention may be readily carried into effect, it' will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a lateral view, partly in section, of an embodiment of an automatic switch of the present invention;

FIG. 2 is a front view of the embodiment illustrated in FIG.

FIG. 3 is a schematic diagram of the switch lock;

FIG. '4 is a schematic diagram, partly in section, of part of the embodiment of FIG. 1; and

FIG. 5 is a schematic diagram, partly in section, of the leaf spring adjusting device.

In the FIGS., the same components are identified by the same reference numerals.

In FIG. 1, the automatic switch comprises a mount 1, overcurrent trips in the form of bimetallic strips 2, electromagnetic instantaneous trips 3 and quenching devices 4. The illustrated switch has three poles each of which is provided with an overcurrent trip 2, an instantaneous trip 3 and a quenching device 4. In accordance with a feature of our invention, the frame is provided with a plate 5 which extends a distance from the base of the mount.

At the plate 5, a switch lock 6 is arranged above the instantaneous trips 3 and the quenching devices 4. The trips 3 and devices 4 are laterally inserted into the mount. The strips 2 are placed in a recess 7 at the base or the mount 1. The strips 2 have supports 8 which are constructed to act as a stationary contact part 9 and as an arc guide horn 10. This eliminates additional terminal points which would otherwise introduce contact resistances in the current path and eliminates the need for separate attachments for the bimetallic strips.

A movable contact portion 11 is pivotally mounted on the instantaneous trip 3 by means of a current conducting pin 16. The instantaneous trip 3 comprises a coil or winding 12, a

return iron 13 and an armature 14 at a bracket 15 attached to the return iron 13. The ends of the coil 12 are soldered to the bracket 15, which may comprise copper, and to a frame terminal 17, respectively.

The current flowing in the switch passes through the frame terminal 18 to the bimetallic strip 2, then through the carrier 8 to the stationary contact part 9, and finally, through the movable contact portion 11 to the winding 12 and the frame ter minal 17. The instantaneous trip 3 with the movable contact 11 is laterally insertable and is easily installed and, consequently, no additional terminal connections are required which would otherwise introduce contact resistance. A spring 19 is inserted between the movable contact 11 and the return iron 13 of the instantaneous trip 3 and produces the required contact pressure.

After the movable contact 11 is released by means of pull rods or lugs 36, the spring 19 acts as a switch-on spring. The pull lugs 36 surround the movable contact 11 with a clearance adequate to permit the contacts to impact independent of the switch lock. The armature 14 produces the impact of contacts 11 by acting as a tie bar having an extension 20 which bears against the movable contact 11. The armature 14 passes through the movable contact 11 thereby permitting the structural width of the switch to be relatively narrow. A striker 21 is affixed to the armature side opposite the extension 20. The striker 21 functions to unlatch the switch lock 6.

FIG. 3 illustrates how the pull lugs 36 engage a rocker flap 27 with their other ends. The rocker flap 27 is spring-loaded by means of a restoring spring which is arranged so that it can overcome the force of the three springs 19. The rocker flap 27 is pivoted at points 29 and at a distance from the pivot points, a knuckle joint system 32 is connected with a tommy pivot 31. The knuckle joint system 32 is also connected to a U-shaped bent portion 30. A pivotally mounted latch 33, which acts as a support for the knuckle joint system, is engaged by the trip device for unlatching the switch lock 6.

FIGS. 1 and 3 illustrate the coaction of the striker 21 and the latch 33. The striker 21, which appears three times in a three pull switch, operates on a release member 44, which release member also contacts the latch 33, thereby releasing the knuckle joint system 32, so that the actual switch lock 6 collapses into itself and the pulling lugs 36 are loaded by the rocker flap 27.

The coaction between the bimetallic strips 2 and the switch lock 6 is illustrated inFIG. 4. The bimetallic strips 2 act upon a connecting slide 40 which cooperates with other components housed in a chamber in the base or mount 1 of the switch (FIG. 1). These components function as a deflection lever 43 (FIG. 4) which coacts with an adjustment rocker 41 pivoted at a pivot point 42 (FIG. 4). The components further comprise a release rod 39, which acts on the release member 44 (FIG. 1) in the same manner as the striker 21. The release point of the bimetallic strip is set by the knurled screw 37. The knurled screw 37 aflects 'an adjustment rod 38 in a manner whereby the adjustment rocker 41, which is preferably springloaded in the direction of the adjustment rod 38, is displaced (FIG. 4). A change thus occurs in the pivot point of the deflection lever 43, resulting in a change in the release time point of the release member 44, via the release rod 39. The coaction of the foregoing components is illustrated in FIGS. 3 and 4.

In order to close or make the switch conductive, the lever 35 must be rotated clockwise, whereby the rocker flap 27 is rotated about its pivot point 29, via the knuckle joint system 32, while the pulling lugs 36 permit the switching on of the contacts by releasing the spring-force of the springs 19. The rocker flap 27 is spring-loaded by a spring 28, so that the knuckle joint system 32 tries to expand. Since the lever 35 is also loaded by the restoring force of a spring 45 (FIG. 1), the latch 33 provides automatic restoration of the release components.

As shown in FIG. 5, the striker 21 penetrates the plate and is spring-loaded by the leaf spring 22 located outside plate 5. The leaf spring 22 is bent so that it has two legs 23, 24 at substantially right angles to each other. The leg 23 is prestressed so that it acts on the armature in the reset direction or also against the plate 5. The leg 24 is braced against two fixed points 25, between which the leg 24 can be stressed by an adjusting device. The adjusting device can comprise a screw or bolt 26 which threadably engages the return iron 13 of the instantaneous trip 3, the latter being provided with a suitable thread. The head of the bolt or screw 26 enters the leg 24 of the flat spring 22 so as to bear against the leg 24. When the screw 26 is turned into the return iron 13, the leg 24 of the spring 22 is bent, thereby reducing the spring tension with which the leg 23 presses against the armature 14. The fore going mechanism constitutes the simplest possible adjustment means for a tripping device.

Since no switching shaft is present in the switching device of the invention, the dimensions of the switching device can be kept relatively small. After the instantaneous trip 3 and the arc quenching device 4 are laterally inserted, a cap is placed which covers the switch lock 6 and prevents the other parts from slipping out. The cap protects the frame terminals 17, 18 from being turned and from being touched. The operating lever 35 may be placed in the cap 34 so that a form fit engagement results between the lever 35 and the tommy pivot 31. Alternatively, the lever 35 may be affixed to the pivot 31, which extends through the cap 34 after the cap is positioned. The means for securing the cap is not illustrated in the drawing. The means for securing the cap may comprise any suitable means such as, for example, a screw attachment or snap-on elements. The knurled screw 37, which extends through the cap 34, is used to adjust the overcurrent trip device.

While the invention has been described by means of a specific example and in a specific embodiment, we do not wish to be limited thereto for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

We claim: 7

1. An automatic electric switch having a base covered by a cap and including a stationary contact portion, a movable contact portion, an electromagnetic instantaneous release, a thermal excess current release, said instantaneous release and said thermal excess current release being mechanically coupled to and in electrically conductive connection with said stationary contact portion and operatively coupled to said movable contact portion, an arc quenching device connected to the stationary and movable contact portions and actuating means for actuating the movable contact portion of the switch mounted on a plate which extends at a distance toward the bottom of the base, the instantaneous release being located between the plate and the base, said instantaneous release being a holder for the movable contact portion and being inserted as a structural unit between the plate and the base.

2. An automatic electric switch as claimed in claim 1, wherein the plate is rigidly held at the base, and further comprising a space formed between the plate and the base for the instantaneous release, said space opening in the area of an edge of said plate.

3. An automatic electric switch as claimed in claim 1, further comprising a stationarily mounted contact pressure spring functioning as a closing spring and positioned and braced between the contact portion and the instantaneous release.

4. An automatic electric switch as claimed in claim 1, wherein the instantaneous release has an armature which is a tie bar for the current limiting separation of the stationary contact portion and the movable contact portion.

5. An automatic electric switch as claimed in claim 1, further comprising a pulling rod around the movable contact portion, and wherein the switch lock has a rocker and the movable contact portion coacts with the rocker of said switch lock via the pulling rod.

6. An automatic electric switch as claimed in claim 4, further comprising an extension, and wherein the armature of the instantaneous release penetrates the movable contact portion and is connected to the extension to control the opening of said movable contact portion. 

1. An automatic electRic switch having a base covered by a cap and including a stationary contact portion, a movable contact portion, an electromagnetic instantaneous release, a thermal excess current release, said instantaneous release and said thermal excess current release being mechanically coupled to and in electrically conductive connection with said stationary contact portion and operatively coupled to said movable contact portion, an arc quenching device connected to the stationary and movable contact portions and actuating means for actuating the movable contact portion of the switch mounted on a plate which extends at a distance toward the bottom of the base, the instantaneous release being located between the plate and the base, said instantaneous release being a holder for the movable contact portion and being inserted as a structural unit between the plate and the base.
 2. An automatic electric switch as claimed in claim 1, wherein the plate is rigidly held at the base, and further comprising a space formed between the plate and the base for the instantaneous release, said space opening in the area of an edge of said plate.
 3. An automatic electric switch as claimed in claim 1, further comprising a stationarily mounted contact pressure spring functioning as a closing spring and positioned and braced between the contact portion and the instantaneous release.
 4. An automatic electric switch as claimed in claim 1, wherein the instantaneous release has an armature which is a tie bar for the current limiting separation of the stationary contact portion and the movable contact portion.
 5. An automatic electric switch as claimed in claim 1, further comprising a pulling rod around the movable contact portion, and wherein the switch lock has a rocker and the movable contact portion coacts with the rocker of said switch lock via the pulling rod.
 6. An automatic electric switch as claimed in claim 4, further comprising an extension, and wherein the armature of the instantaneous release penetrates the movable contact portion and is connected to the extension to control the opening of said movable contact portion. 